1. Field of the Invention
The present invention relates generally to hemo-analysis. More particularly, the invention relates to a testing disk for handling and carrying samples and also to a method and apparatus for analyzing, storing, displaying and printing data from blood typing and other related procedures.
2. Description of the Prior Art
Blood grouping is a routine procedure for categorizing human blood into one of four classifications: A, B, AB or O. Currently, blood grouping is accomplished by inducing agglutination, i.e., clumping, in red blood cell suspensions. To perform this procedure a patient's blood sample is clotted and then centrifuged to separate the red blood cells from the blood serum. A small amount of red blood cells is mixed with a diluent and a portion of this test solution is introduced into a test tube. The test tube also contains either anti-A-serum, anti-B-serum or anti-AB-serum. At various stages of the procedure, reagents facilitating and enhancing immunological reactions are added to the test solution and the resulting solution is incubated, centrifuged and agitated. A sample is then removed from the solution and visually analyzed under a microscope to determine whether cell agglutination has occurred.
A sample which agglutinates in the presence of anti-A reagent, but does not agglutinate with the presence of anti-B reagent is identified as blood type A. Similarly, a sample which agglutinates with anti-B reagent but does not agglutinate with anti-A reagent is classified as blood type B. A sample which agglutinates with both anti-A and anti-B reagents is classified as blood type AB, and a sample which does not respond to either reagent is classified as blood type O.
Presently, a variety of factors combine to make blood grouping procedures costly, error prone, slow to complete and potentially dangerous to technicians completing the procedures. For example, blood grouping procedures are usually performed manually by a trained technician. The technician subjectively evaluates the procedure's results and, consequently, blood grouping procedures are slow, labor intensive and error prone. Because of the subjective nature of sample evaluation, results from these tests are far from uniform. Such factors as the technician's experience, training and fatigue strongly influence the technician's evaluation of the sample. Unfortunately, the consequences of an error can be fatal.
Blood grouping procedures also require the use of a variety of glass objects, including microscope slides, cover slips and pipettes. These glass objects are non-reusable, must be discarded after use and are hazardous if cracked or shattered. Furthermore, the glass objects are contaminated with potentially dangerous human blood and special care must be exercised for proper and safe disposal. Glass object disposal and replacement results in unwanted and unnecessary expense for performing blood grouping procedures.
Additionally, the biological fluid to be tested is usually mixed with other fluids, incubated, centrifuged and microscopically examined. During all stages of the immuno-analyses procedure the technician is routinely exposed to human blood potentially carrying infectious and possibly lethal diseases. In order to minimize handling and reduce exposure to fragile glass objects, it is desirable to perform the entire analyses using only one sample holder.
Currently, several models of sample holders attempt to reduce blood sample handling during blood grouping and other related procedures. In general, current sample holders are designed to facilitate blood sample centrifuging and separations. Generally, such sample holders are disk-shaped and employ contoured chambers and passages to promote sample mixing and separation. Biological fluids placed within these disks are mixed and separated by being centrifugally forced over chamber walls or through a variety of passages. These disk designs generally do not allow sample testing or microscopic analysis while the sample is held in the disk. Consequently, a need exists for a sample holder to aid sample preparation, handling and microscopic analysis.
Additionally, as discussed above, blood grouping and other immunological tests are generally labor-intensive and error-prone. In order to reduce manual sample handling and increase testing reliability, it is desirable to integrate a sample holder into a fully-automated analysis system. Current analysis systems generally perform immuno-analyses in one of two ways.
The first type of analysis system examines physical characteristics of mounted and stained blood specimens. In general, the specimens are mounted on glass slides and stained with compounds which enhance identification of cells or physical objects within the cells based upon recognizable physical characteristics. These physical characteristics may then be measured, enhanced and tentatively identified. Many of these systems create digitized images of the examined cells and objects, store and manipulate the acquired data and then print a permanent record of testing and analyses results.
The second type of analysis system determines the presence of immunological responses within the specimen. In general, blood samples are mixed and reacted with other substances within the analysis system. If the particles within the sample agglutinate, the solution generally becomes turbid and the specimen's optical density increases and may be measured photometrically. The degree of turbidity depends upon the degree of agglutination and is measured photometrically. The measured data is then processed to determine the extent of agglutination in the sample. In contrast to the first type of analysis systems, this type of analysis system cannot create digitized images of cells or cell features.
Thus, the prior art has been described with reference to blood grouping. However, the same limitations of utilizing manual procedures evident with blood grouping apply to other blood analysis procedures such as, for example, Rh typing, anti-body screening, anti-body identification and donor/recipient compatibility cross matching.
As is evident from the above discussion, the analysis systems which microscopically examine physical characteristics of specimen cells do not analyze immunological reactions. In contrast, analysis systems which focus on immunological reactions do not microscopically examine physical characteristics of specimen cells. As a result, a need exists for an automated system integrating a useful sample holder which also analyzes immunological reactions including creating, storing and printing digitized images of immunological responses.